Photosensitive resin composition, printed wiring board, substrate for disposing semiconductor chips, semiconductor device and processes for producing a printed wiring board, a substrate for disposing semiconductor chips and a semiconductor device

ABSTRACT

A photosensitive resin composition comprising an oxygen sensitizer and a cis-diene-substituted polyamic acid or a polyimide. A printed wiring board, a substrate for disposing semiconductor chips and a semiconductor device prepared by coating a substrate with the photosensitive resin composition and forming fine patterns by exposure to radiation. Processes for producing a printed wiring board, a substrate for disposing semiconductor chips and a semiconductor device, which comprise coating a substrate with the photosensitive resin composition and forming fine patterns by crosslinking cis-diene by oxidation polycondensation with singlet oxygen generated by exposure of the oxygen sensitizer to radiation. The photosensitive resin composition is of the negative type and exhibits high sensitivity and high resolution. The photosensitive resin composition can form a resin layer having excellent heat resistance.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a photosensitive resin composition, aprinted wiring board, a substrate for disposing semiconductor chips, asemiconductor device and processes for producing a printed wiringsubstrate, a substrate for disposing semiconductor chips and asemiconductor device. More particularly, the present invention relatesto a photosensitive resin composition of the negative type which can beapplied to production of semiconductor elements and circuit wiringboards, can exhibit high sensitivity and high resolution and can formresin layers having excellent heat resistance; a printed wiringsubstrate, a substrate for disposing semiconductor chips and asemiconductor device obtained by using the photosensitive resincomposition; and processes for producing a printed wiring substrate, asubstrate for disposing semiconductor chips and a semiconductor deviceusing the photosensitive resin composition.

2. Description of Related Art

As electronic instruments are recently used in portable forms,electronic instruments rapidly become lighter, thinner, shorter andsmaller and have more advanced functions. Due to the above progress,semiconductor elements become smaller and more highly integrated. Forexample, in semiconductor circuits formed on semiconductor chips, thecircuits themselves are more highly integrated, the circuits becomefiner due to the decrease in the size of packages and materials sealingthe packages to protect chips become thinner. It is generally conductedthat protecting layers such as passivation layers are used on circuitsat the surface of chips to assure the reliability. To achieve furtherintegration, circuits are formed in multi-layers with inter-layerinsulation disposed between the layers.

With respect to semiconductor packages in which semiconductor chips aresealed, new packaging technologies which can achieve integration to highdensities such as the ball grid array (BGA), the chip scale package(CSP) and the multi-chip module (MCM) have been developed. In thesesemiconductor packages, electric connection between electrodes insemiconductor chips and printed wiring boards is achieved by usinginterposers which are substrates constituted with various materials suchas plastic and ceramics. Because the circuits formed on the substratesare introduced into the inside of semiconductors having decreased sizes,the circuits have much finer wiring and much higher degree ofintegration than those in conventional printed wiring circuits.Therefore, it is necessary that the fine circuits be protected byadopting the form of packaging. New technologies are developed also withrespect to printed wiring boards to which these semiconductor packagesare disposed. For example, in the build-up process, wiring layers aresuccessively formed on a substrate with an insulation resin disposedbetween the layers to increase the density of wiring.

It is commonly required for these protecting resins and inter-layerinsulation resins that the resins have high heat resistance so that theresin can withstand temperatures as high as 200 to 300° C. duringbonding and disposing chips and workability in formation of holes sothat electric conductivity is provided at junctions of wirings andbetween insulation layers. In particular, with respect to protectingfilms for interposers and inter-layer insulation films for circuitboards formed in accordance with the build-up process which must beworked on substrates, it is required that the resins have workability atlow temperatures so that the working does not cause damage to thesubstrates.

Heretofore, polyimides have been used for applications which requireheat resistance such as protecting films of semiconductor chips andepoxy resins have been used for applications which require working atlow temperatures such as protecting films on circuit substrates andinter-layer insulation films. For pattern working such as formation ofholes suitable for highly integrated circuit wiring, it is advantageousthat the patterns are formed by utilizing the photomechanical process(the photographic process), i.e., by using photosensitive resins such asheat resistant photosensitive polyimide and epoxy resins.

As for the polyimide resins, photosensitive polyimides have beendeveloped and used (for example, Japanese Patent Application PublicationShowa 55(1980)-30207 and Japanese Patent Application Laid-Open No. Showa54(1979)-145794). In general, these photosensitive polyimides formcrosslinked structures by photoradical polymerization of(metha)acrylates introduced into the carboxyl group of polyamic acidwhich is used as the precursor of the polyimide. Pattern working such asformation of holes is conducted by utilizing the difference insolubility into developer between crosslinked area and uncrosslinkedarea. When the above polyamic acid is converted into a polyimide, it isnecessary that the (metha)acryloyl group bonded to the carboxyl group beremoved. Therefore, the ring closure for forming such an imide structurefrom the polyamic acid requires stronger heating than that required forthe ring closure for forming conventional polyimides. Moreover, becausethe properties of the polyimide such as heat resistance and mechanicalproperties are markedly deteriorated when the removed (metha)acrylatefragment is left remaining in the polyimide, the removed (metha)acrylatefragment must be decomposed and vaporized at high temperature in orderthat the polyimide can exhibit the excellent characteristic propertiesthereof. Thus, it is necessary that the photosensitive polyimides beworked at temperatures still higher than those for conventionalpolyimides. To overcome the problem of working at high temperatures, ithas been proposed that (metha)acrylate moiety are incorporated into sidechains of polyimides which has been treated by ring closure in advanceso that low temperature workability is excellent (Japanese PatentApplication Laid-Open No. Showa 59(1984)-108031 and the like otherapplications). However, the (metha)acrylate moiety are left remaining inthese resins after working and the properties such as heat resistancedeteriorate.

As for the epoxy resins, various types of photosensitive epoxy resinsare actually used as solder resists for protection of circuit wiringsand resins for inter-layer insulation for the build-up process. However,no epoxy resins exhibit satisfactory properties such as heat resistanceand flexibility to follow deformation of thinner substrates contained inthinner packages.

As the photosensitive material composition advantageously used forresists exhibiting high resolution and high sensitivity, aphotosensitive material composition comprising a fullerene withoutphotosensitive groups and a photosensitive agent such as a diazidecompound has been proposed (Japanese Patent No. 2814174). However, thiscomposition has drawbacks in that the solution of the composition haslow viscosity because the composition is composed of a fullerene and alow molecular weight diazide so it is difficult to coat an uniform filmhaving a sufficient thickness. And the coating film formed bypolymerization and crosslinking between the fullerene and the diazidehas inferior mechanical strength and poor heat resistance. Moreover,that a fullerene which is very expensive at the present time is used inan amount five folds as much as the amount of the diazide to causeeconomic disadvantage.

SUMMARY OF THE INVENTION

An object of the present invention is to provide a photosensitive resincomposition of the negative type which can be applied to production ofsemiconductor elements and circuit wiring boards, exhibits highsensitivity and high resolution and can form resin layers havingexcellent heat resistance; a printed wiring board, a substrate fordisposing semiconductor chips and a semiconductor device using thephotosensitive resin composition; and processes for producing a printedwiring board, a substrate for disposing semiconductor chips and asemiconductor device using the photosensitive resin composition.

As the result of extensive studies by the present inventors to overcomethe above problems, it was found that a photosensitive resin compositionhaving remarkably improved photosensitivity and heat resistance can beobtained by using a polyamic acid or polyimide having a cis-dienestructure at side chains in combination with an oxygen sensitizer andthat a resin layer having excellent heat resistance can be formed byforming a layer of the photosensitive resin composition, applyingradiation to the oxygen sensitizer and crosslinking the cis-diene groupby following oxidation polycondensation with singlet oxygen generated byexposure of radiation to the oxygen sensitizer in the presence ofoxygen. The present invention has been completed based on thisknowledge.

The present invention provides:

(1) A photosensitive resin composition which comprises an oxygensensitizer and a cis-diene-substituted polyamic acid or polyimide havinga structural unit represented by general formula [1]:

 wherein at least one of R¹, R², R³ and R⁴ represents a monovalentorganic group having a cis-diene structure; and the rest of R¹, R², R³and R⁴ each independently represents hydrogen, hydroxyl group, carboxylgroup, an alkyl group having 1 to 20 carbon atoms or an alkoxy grouphaving 1 to 20 carbon atoms;

(2) A photosensitive resin composition which comprises an oxygensensitizer and a cis-diene-substituted polyamic acid or polyimide havinga structural unit represented by general formula [2]:

 wherein at least one of R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹ and R¹² representsa monovalent organic group having a cis-diene structure; and the rest ofR⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹ and R¹² each independently representshydrogen, hydroxyl group, carboxyl group, an alkyl group having 1 to 20carbon atoms or an alkoxy group having 1 to 20 carbon atoms;

(3) A photosensitive resin composition which comprises an oxygensensitizer and a cis-diene-substituted polyamic acid or polyimide havinga structural unit represented by general formula [3]:

 wherein at least one of R¹³, R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸, R¹⁹ and R²⁰represents a monovalent organic group having a cis-diene structure; therest of R¹³, R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸, R¹⁹ and R²⁰ each independentlyrepresents hydrogen, hydroxyl group, carboxyl group, an alkyl grouphaving 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbonatoms; and R²¹ represents oxygen, sulfur or an alkylene group, analkylidene group or an alkyleneoxy group having 1 to 4 carbon atoms;

(4) A photosensitive resin composition which comprises an oxygensensitizer and a cis-diene-substituted polyamic acid or polyimide havinga structural unit represented by general formula [4]:

 wherein at least one of R²², R²³, R²⁴ and R²⁵ represents a monovalentorganic group having a cis-diene structure; the rest of R²², R²³, R²⁴and R²⁵ each independently represents hydrogen, hydroxyl group, carboxylgroup, an alkyl group having 1 to 20 carbon atoms or an alkoxy grouphaving 1 to 20 carbon atoms; X¹ and X² each independently representsoxygen, sulfur or an alkylene group, an alkylidene group or analkyleneoxy group which each has 1 to 4 carbon atoms and may havesubstituents; Ar¹ and Ar² each independently represents a divalentaromatic group; and l₁, l₂, m₁ and m₂ each independently represents 0 or1 except that m₁ represents 1 when l₁ represents 1 and m₂ represents 1when l₂ represents 1;

(5) A photosensitive resin composition which comprises an oxygensensitizer and a cis-diene-substituted polyamic acid or polyimide havinga structural unit represented by general formula [5]:

 wherein at least one of R²⁶, R²⁷, R²⁸, R²⁹, R³⁰, R³¹, R³² and R³³represents a monovalent organic group having a cis-diene structure; therest of R²⁶, R²⁷, R²⁸, R²⁹, R³⁰, R³¹, R³² and R³³ each independentlyrepresents hydrogen atom, hydroxyl group, carboxyl group, an alkyl grouphaving 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbonatoms; Y¹ represents oxygen, sulfur or an alkylene group, an alkylidenegroup or an alkyleneoxy group which each has 1 to 4 carbon atoms and mayhave substituents; and n₁ represents 0 or 1;

(6) A photosensitive resin composition described in any of (1), (2),(3), (4) and (5), wherein the cis-diene structure is a cyclopentadiene,furan, thiophene or pyrrole structure;

(7) A photosensitive resin composition described in any of (1), (2),(3), (4), (5) and (6), wherein the oxygen sensitizer is a fullerene;

(8) A printed wiring board which is prepared by coating a printed wiringsubstrate with a photosensitive resin composition described in any of(1), (2), (3), (4), (5), (6) and (7), and forming fine patterns byexposure of radiation;

(9). A substrate for disposing semiconductor chips which is prepared bycoating a printed wiring substrate with a photosensitive resincomposition described in any of (1), (2), (3), (4), (5), (6) and (7),and forming fine patterns by exposure of radiation;

(10) A semiconductor device which is prepared by coating a substrate onwhich semiconductor chips are disposed with a photosensitive resincomposition described in any of (1), (2), (3), (4), (5), (6) and (7),and forming fine patterns by exposure of radiation;

(11) A process for producing a printed wiring board which comprisescoating a printed wiring substrate with a photosensitive resincomposition described in any of (1), (2), (3), (4), (5), (6) and (7),and forming fine patterns by crosslinking the cis-diene group byfollowing oxidation polycondensation with singlet oxygen generated byexposure of radiation to the oxygen sensitizer in the presence ofoxygen;

(12) A process for producing a substrate for disposing semiconductorchips which comprises coating a printed wiring substrate with aphotosensitive resin composition described in any of (1), (2), (3), (4),(5), (6) and (7), and forming fine patterns by crosslinking thecis-diene group by polycondensation with oxidation with singlet oxygengenerated by exposure of radiation to the oxygen sensitizer; and

(13) A process for producing a semiconductor device which comprisescoating the surface for forming a conductive circuit of a substrate onwhich semiconductor chips are disposed with a photosensitive resincomposition described in any of (1), (2), (3), (4), (5), (6) and (7),and forming fine patterns by crosslinking the cis-diene group bypolycondensation with oxidation with singlet oxygen generated byexposure of radiation to the oxygen sensitizer.

The preferable embodiments of the present invention include:

(14) A photosensitive resin composition described in (1), wherein thecontent of the structural unit represented by formula [1] is 30% by molor more of the total diamine units;

(15) A photosensitive resin composition described in (2), wherein thecontent of the structural unit represented by formula [2] is 30% by molor more of the total diamine units;

(16) A photosensitive resin composition described in (3), wherein thecontent of the structural unit represented by formula [3] is 30% by molor more of the total diamine units;

(17) A photosensitive resin composition described in (4), wherein thecontent of the structural unit represented by formula [4] is 30% by molor more of the total diamine units;

(18) A photosensitive resin composition described in (5), wherein thecontent of the structural unit represented by formula [5] is 30% by molor more of the total diamine units;

(19) A photosensitive resin composition described in any of (1), (2),(3), (4) and (5), wherein the molecular weight of the polyamic acid orthe polyimide is 5,000 or greater; and

(20) A photosensitive resin composition described in any of (1), (2),(3), (4) and (5), wherein the amount of the oxygen sensitizer is 0.01 to20 parts by weight per 100 parts by weight of the polyamic acid or thepolyimide.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The first embodiment of the photosensitive resin composition of thepresent invention is the composition which comprises an oxygensensitizer and a cis-diene-substituted polyamic acid or polyimide havinga structural unit represented by general formula [1]:

In general formula [1], at least one of R¹, R², R³ and R⁴ represents amonovalent organic group having a cis-diene structure; and the rest ofR¹, R², R³ and R⁴ each independently represents hydrogen, hydroxylgroup, carboxyl group, an alkyl group having 1 to 20 carbon atoms or analkoxy group having 1 to 20 carbon atoms.

The second embodiment of the photosensitive resin composition of thepresent invention is the composition which comprises an oxygensensitizer and a cis-diene-substituted polyamic acid or polyimide havinga structural unit represented by general formula [2]:

In general formula [2], at least one of R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹ andR¹² represents a monovalent organic group having a cis-diene structure;and the rest of R⁵, R⁶, R⁷, R⁸, R⁹, R¹⁰, R¹¹ and R¹² each independentlyrepresents hydrogen, hydroxyl group, carboxyl group, an alkyl grouphaving 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbonatoms.

The third embodiment of the photosensitive resin composition of thepresent invention is the composition which comprises an oxygensensitizer and a cis-diene-substituted polyamic acid or polyimide havinga structural unit represented by general formula [3]:

In general formula [3], at least one of R¹³, R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸,R¹⁹ and R²⁰ represents a monovalent organic group having a cis-dienestructure; the rest of R¹³, R¹⁴, R¹⁵, R¹⁶, R¹⁷, R¹⁸, R¹⁹ and R²⁰ eachindependently represents hydrogen, hydroxyl group, carboxyl group, analkyl group having 1 to 20 carbon atoms or an alkoxy group having 1 to20 carbon atoms; and R²¹ represents oxygen, sulfur or an alkylene group,an alkylidene group or an alkyleneoxy group having 1 to 4 carbon atoms.

The fourth embodiment of the photosensitive resin composition of thepresent invention is the composition which comprises an oxygensensitizer and a cis-diene-substituted polyamic acid or polyimide havinga structural unit represented by general formula [4]:

In general formula [4], at least one of R²², R²³, R²⁴ and R²⁵ representsa monovalent organic group having a cis-diene structure; the rest ofR²², R²³, R²⁴ and R²⁵ each independently represents hydrogen, hydroxylgroup, carboxyl group, an alkyl group having 1 to 20 carbon atoms or analkoxy group having 1 to 20 carbon atoms; X¹ and X² each independentlyrepresents oxygen, sulfur or an alkylene group, an alkylidene group oran alkyleneoxy group which each has 1 to 4 carbon atoms and may havesubstituents; Ar¹ and Ar² each independently represents a divalentaromatic group; and l₁, l₂, m₁ and m₂ each independently represents 0 or1 except that m₁ represents 1 when l₁ represents 1 and m₂ represents 1when l₂ represents 1.

The fifth embodiment of the photosensitive resin composition of thepresent invention is the composition which comprises an oxygensensitizer and a cis-diene-substituted polyamic acid or polyimide havinga structural unit represented by general formula [5]:

In general formula [5], at least one of R²⁶, R²⁷, R²⁸, R²⁹, R³⁰, R³¹,R32 and R³³ represents a monovalent organic group having a cis-dienestructure; the rest of R²⁶, R²⁷, R²⁸, R₂₉, R³⁰, R³¹, R³² and R³³ eachindependently represents hydrogen atom, hydroxyl group, carboxyl group,an alkyl group having 1 to 20 carbon atoms or an alkoxy group having 1to 20 carbon atoms; Y¹ represents oxygen, sulfur or an alkylene group,an alkylidene group or an alkyleneoxy group which has 1 to 4 carbonatoms and may have substituents; and n₁ represents 0 or 1.

In the fourth and fifth embodiments of the composition of the presentinvention, the cis-diene-substituted polyamic acid or polyimide havingthe structural unit represented by general formula [4] and [5],respectively, are characterized in that the main chain is bonded to themeta-positions of an aromatic ring substituted with a monovalent organicgroup having the cis-diene structure. When the main chain is bonded tothe meta-positions of the aromatic ring, molecular packing such ascrystallinity of the polyamic acid or the polyimide tends to decrease.In particular, the resin having the cis-diene structure shows improvedsolubility in a developer. As the result, when optical patterns areformed, the difference in solubility into a developer between unexposedportions which should be dissolved into the developer and exposedportions which are crosslinked is remarkably exhibited. Therefore, theability to form patterns is remarkably improved in that excellentcontrast is exhibited by exposure to a small amount of light, resinpatterns having excellent shapes are easily obtained and resins of theunexposed portions can be removed completely.

In the composition of the present invention, the polyamic acid or thepolyimide may have a single type of the structural unit represented byany of general formulae [1] to [5] or two or more types of suchstructural units in the form of a copolymer. The composition of thepresent invention may comprise a single type or a mixture of two or moretypes of the cis-diene-substituted polyamic acids or polyimides havingthe structural units represented by general formulae [1] to [5]. Thecomposition of the present invention may be a mixture of thecis-diene-substituted polyamic acids or polyimides having the structuralunits represented by general formulae [1] to [5] and polyamic acids orpolyimides having no structural units represented by general formulae[1] to [5].

Examples of the monovalent organic group having a cis-diene structure ingeneral formulae [1] to [5] include —CH₂O—CO—D, —O—CO—D, —CO—O—CH₂D,—CH₂O—CH₂—D, —O—CH₂—D, —NH—CO—D and —CO—NH—CH₂—D. D represents acis-diene structure. Examples of the cis-diene structure represented byD include cyclopentadienyl group, furyl group, pyrrolyl group, thienylgroup, 2,4-pyranyl group, isobenzofuranyl group, indolydinyl group andquinolidinyl group. Among these groups, cyclopentadienyl group, furylgroup, thienyl group and pyrrolyl group are preferable.

In general formulae [1] to [5], examples of the alkyl group having 1 to20 carbon atoms include methyl group, ethyl group, butyl group, pentylgroup, hexyl group, heptyl group, octyl group, decyl group and laurylgroup. Among these groups, methyl group, ethyl group, propyl group,butyl group and pentyl group are preferable.

In general formulae [1] to [5], examples of the alkoxy group having 1 to20 carbon atoms include methoxy group, ethoxy group, propoxy group,butoxy group, pentyloxy group, hexyloxy group, lauryloxy group andphenoxy group. Among these groups, methoxy group, ethoxy group, butoxygroup and pentyloxy group are preferable.

In general formulae [3] to [5], examples of the alkylene group having 1to 4 carbon atoms include methylene group, ethylene group, propylenegroup, isopropylidene group and butylene group. Examples of thealkyleneoxy group having 1 to 4 carbon atoms include methyleneoxy group,ethyleneoxy group, propyleneoxy group and butyleneoxy group.

The process for producing the cis-diene-substituted polyamic acids andpolyimides having structural units represented by general formulae [1]to [5] which are used in the present invention is not particularlylimited. For example, the polyamic acid and the polyimide can beproduced by using a diamine represented by one of general formulae [6]to [10] and a dianhydride of a polycarboxylic acid as the materials.

In general formula [6], at least one of R³⁴, R³⁵, R³⁶ and R³⁷ representshydroxyl group; and the rest of R³⁴, R³⁵, R³⁶ and R³⁷ each independentlyrepresents hydrogen, carboxyl group, an alkyl group having 1 to 20carbon atoms or an alkoxy group having 1 to 20 carbon atoms.

In general formula [7], at least one of R³⁸, R³⁹, R⁴⁰, R⁴¹, R⁴², R⁴³,R⁴⁴ and R⁴⁵ represents hydroxyl group; and the rest of R³⁸, R³⁹, R⁴⁰,R⁴¹, R⁴², R⁴³, R⁴⁴ and R⁴⁵ each independently represents hydrogen,carboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxygroup having 1 to 20 carbon atoms.

In general formula [8], at least one of R⁴⁶, R⁴⁷, R⁴⁸, R⁴⁹, R⁵⁰, R⁵¹,R⁵² and R⁵³ represents hydroxyl group; the rest of R⁴⁶, R⁴⁷, R⁴⁸, R⁴⁹,R⁵⁰, R⁵¹, R⁵² and R⁵³ each independently represents hydrogen, carboxylgroup, an alkyl group having 1 to 20 carbon atoms or an alkoxy grouphaving 1 to 20 carbon atoms; and R⁵⁴ represents oxygen, sulfur, analkylene group, an alkylidene group or an alkyleneoxy group having 1 to4 carbon atoms.

In general formula [9], at least one of R⁵⁵, R⁵⁶, R⁵⁷ and R⁵⁸ representshydroxyl group, hydroxymethyl group or carboxyl group; the rest of R⁵⁵,R⁵⁶, R⁵⁷ and R⁵⁸ each independently represents hydrogen, an alkyl grouphaving 1 to 20 carbon atoms or an alkoxy group having 1 to 20 carbonatoms; X³ and X⁴ each independently represents oxygen, sulfur or analkylene group, an alkylidene group or an alkyleneoxy group which eachhas 1 to 4 carbon atoms and may have substituents; Ar³ and Ar⁴ eachindependently represents a divalent aromatic group; and l₃, l₄, m₃ andm₄ each independently represents 0 or 1 except that m₃ represents 1 whenl₃ represents 1 and m₄ represents 1 when l₄ represents 1.

In general formula [10], at least one of R⁵⁹, R⁶⁰, R⁶¹, R⁶², R⁶³, R⁶⁴,R⁶⁵ and R⁶⁶ represents hydroxyl group, hydroxymethyl group or carboxylgroup; the rest of R⁵⁹, R⁶⁰, R⁶¹, R⁶², R⁶³, R⁶⁴, R⁶⁵ and R⁶⁶ eachindependently represents hydrogen, an alkyl group having 1 to 20 carbonatoms or an alkoxy group having 1 to 20 carbon atoms; Y² representsoxygen, sulfur or an alkylene group, an alkylidene group or analkyleneoxy group which each has 1 to 4 carbon atoms and may have asubstituent; and n₂ represents 0 or 1. Atoms substituting hydrogen suchas chlorine are included in the substituent.

Examples of the diamine represented by general formula [6] include2-hydroxy-3-methyl-1,4-phenylenediamine and the like. Examples of thediamine represented by general formula [7] include2,2′-dihydroxy-3,3′-dimethyl-4,4′-diaminobiphenyl and the like. Examplesof the diamine represented by general formula [8] include2,2-bis(3-hydroxy-4-aminophenyl)propane and the like. Examples of thediamine represented by general formula [9] include 3,5-diaminobenzylalcohol, 3,5-diaminophenol and 3,5-diaminobenzoic acid. Examples of thediamine represented by general formula [10] include3,3′-diamino-4,4′-dihydroxybiphenyl,2,2-bis(3-amino-4-hydroxyphenyl)hexafluoropropane and3,5-bis(4-aminophenoxy)benzyl alcohol.

In the present invention, the dianhydride of a polycarboxylic acid whichis reacted with the diamines represented by general formulae [6] to [10]is not particularly limited. Examples of the dianhydride of apolycarboxylic acid include pyromellitic dianhydride, prehniticdianhydride, 3,3′,4,4′-benzophenonetetracarboxylic dianhydride,3,3′,4,4′-biphenyltetracarboxylic dianhydride,4,4′-hexafluoroisopropylidene-diphthalic anhydride,benzenepentacarboxylic dianhydride and mellitic dianhydride. Among thesecompounds, 4,4-hexafluoroisopropylidene-diphthalic dianhydride ispreferably used.

In the present invention, the process for reacting the diaminesrepresented by general formulae [6] to [10] with the dianhydride of apolycarboxylic acid is not particularly limited. The polyamic acid canbe synthesized in accordance with a conventional process ofpolymerization. For example, a polyamic acid having a structural unitrepresented by general formula [11] can be obtained by reacting adiamine represented by general formula [6] with pyromellitic dianhydridein a solvent such as N-methyl-2-pyrrolidone at the room temperature. Apolyimide having a structural unit represented by general formula [12]can be obtained by the ring closure reaction with dehydration of thepolyamic acid having a structural unit represented by general formula[11]. A polyamic acid having a structural unit represented by generalformula [13] can be obtained by reacting a diamine represented bygeneral formula [9] with pyromellitic dianhydride in a solvent such asN-methyl-2-pyrrolidone. A polyimide having a structural unit representedby general formula [14] can be obtained by the ring closure reactionwith dehydration of the polyamic acid having a structural unitrepresented by general formula [13].

The process for incorporating a monovalent organic group having acis-diene structure into the polyamic acid having a structural unitrepresented by general formula [11] or [13] or into the polyimide havinga structural unit represented by general formula [12] or [14] is notparticularly limited. For example, a monovalent organic group having acis-diene structure can be incorporated into hydroxyl group of thepolyamic acid having a structural unit represented by general formula[11] or [13] or the polyimide having a structural unit represented bygeneral formula [12] or [14] by reacting a halogenated compound havingthe cis-diene structure in the presence of a base. When, in generalformula [11], R³⁴ represents methyl group, R³⁵ represents hydroxylgroup, R³⁶ and R³⁷ each represents hydrogen and the halogenated compoundhaving the cis-diene structure is furfuryl bromide, the polyamic acidhaving a structural unit represented by the formula [15] can beobtained. When, in general formula [13], R⁵⁷ represents hydroxyl group,R⁵⁵, R⁵⁶ and R⁵⁸ each represents hydrogen and the halogenated compoundhaving the cis-diene structure is furfuryl bromide, the polyamic acidhaving a structural unit represented by general formula [16] can beobtained.

In the present invention, as the process for producing thecis-diene-substituted polyamic acids having a structural unitsrepresented by general formulae [1] to [5], a diamine having hydroxylgroup can be reacted with a dianhydride of a polycarboxylic acid andthen an organic group having a cis-diene structure can be incorporatedinto the obtained product, as described above. Alternatively, forexample, a diamine having an organic group having a cis-diene structuremay be reacted with a dianhydride of a polycarboxylic acid. Examples ofthe diamine having an organic group having a cis-diene structure include2,5-diamino-6-furfuryloxytoluene,3,3′-difurfuryloxy-4,4′-diaminobiphenyl,2,2-bis(3-furfuryloxy-4-aminophenyl)propane,3,5-diaminobenzyl-2-furoate,1,1,1,3,3,3-hexafluoro-2,2-bis(3-amino-4-furfuryloxyphenyl)propane,3,3′-diamino-4,4′-di(2-furoylamino)biphenyl and3,3′-diamino-4,4′-difurfuryloxybiphenyl. The above diamines can beobtained, for example, by reacting an aromatic dinitro compound havinghydroxyl group, carboxyl group or a hydroxyalkyl group with ahalogenated compound having a cis-diene structure such as furfurylbromide in the presence of a base, followed by reducing the nitro groupin the product. The process for reducing nitro group is not particularlylimited. Examples of the process for reducing nitro group includereduction with hydrazine, catalytic hydrogenation reaction in thepresence of a transition metal catalyst such as nickel, palladium andplatinum and reduction with an aqueous solution of indium and ammoniumchloride.

In the composition of the present invention, examples of the structuralunit represented by general formula [4] include structural unitsexpressed by the following formulae [4-(1)] to [4-(20)] and examples ofthe structural unit represented by general formula [5] includestructural units expressed by the following formulae [5-(1)] to[5-(10)].

In the composition of the present invention, it is preferable that theamount of the structural units represented by general formulae [1] to[5] is 30% by mol or more, more preferably 50% by mol or more and mostpreferably 60% by mol or more of the total amount of the diaminestructural units. When the amount of the structural units represented bygeneral formulae [1] to [5] is less than 30% by mol of the total amountof the diamine structural units, there is the possibility that thecuring property of the photosensitive resin composition deteriorates. Inthe present invention, it is preferable that the molecular weight of thecis-diene-substituted polyamic acids and polyimides having structuralunits represented by general formulae [1] to [5] are 5,000 or greater,more preferably 10,000 to 1,000,000 and most preferably 50,000 to200,000. When the molecular weight of the polyamic acids and thepolyimides are smaller than the above value, there is the possibilitythat obtaining a uniform film becomes difficult. When the molecularweight of the polyamic acids and the polyimides are excessively great,there is the possibility that solubility decreases and forming a uniformfilm becomes difficult.

The cis-diene-substituted polyamic acids and polyimides having thestructural units represented by general formulae [1] to [5], which areused in the composition of the present invention, are soluble insolvents or alkaline aqueous solutions. The polyamic acids and thepolyimides easily react with the singlet oxygen generated by the effectof the oxygen sensitizer and intermediates of polyamic acids and thepolyimides, respectively, having a peroxide group are formed. The formedintermediates immediately react with the adjacent polyamic acids and thepolyimides, respectively, induce crosslinking between each other bypolycondensation and remarkably increase the molecular weight. Due tothis reaction, the polyamic acids and the polyimides become insoluble.The polyamic acids and the polyimides crosslinked by thepolycondensation show remarkably improved heat resistance. Unlikeconventional photosensitive polyimides which are crosslinked by theradical reaction, the photosensitive resin composition of the presentinvention is crosslinked by polycondensation with oxidation of thecis-diene structure by the singlet oxygen. Therefore, the reaction isnot adversely affected by oxygen in the air and the crosslinked resinhas excellent heat resistance.

The oxygen sensitizer used for the composition of the present inventionis not particularly limited. It is preferable that the oxygen sensitizerhas an excited triplet energy of 22.5 kcal/mol or more. Examples of theoxygen sensitizer include methylene blue, rose bengal, hematoporphyrin,tetraphenylporphine, rubrene, fullerene C60, fullerene C70 and fullereneC82. The oxygen sensitizer may be used singly or as a combination of twoor more types. Among these oxygen sensitizers, fullerene C60 andfullerene C70 are preferably used.

In the composition of the present invention, the amount of the oxygensensitizer is not particularly limited. It is preferable that the amountof the oxygen sensitizer is 0.01 to 20 parts by weight and morepreferably 0.1 to 10 parts by weight per 100 parts by weight of thecis-diene-substituted polyamic acid or polyimide having a structuralunit represented by any of general formulae [1] to [5]. When the amountof the oxygen sensitizer is less than the above range, there is thepossibility that the sensitizing effect becomes insufficient. When theamount of the oxygen sensitizer is more than the above range, economicdisadvantage arises and there is the possibility that forming a uniformfilm in accordance with spin coating or bar coating becomes difficult.The composition of the present invention which comprises the highmolecular weight cis-diene-substituted polyamic acid or polyimide andthe oxygen sensitizer has a suitable viscosity when the composition isused as a solution and can be applied to silicon wafers uniformly to anecessary thickness by a spin coater, a bar coater or a curtain coater.Because the resin layer is formed by crosslinking the high molecularweight cis-diene-substituted polyamic acid or polyimide in thecomposition, the formed resin layer has excellent strength and heatresistance. The expensive oxygen sensitizer such as fullerenes is usedin a relatively small amount and the resin layer can be formedeconomically advantageously.

The method of application of the photosensitive resin composition of thepresent invention is not particularly limited. In general, thephotosensitive resin composition is applied to a substrate, worked toform patterns by light exposure and development and then, wherenecessary, heat cured to form a resin layer. The method of forming thecoating film is not particularly limited. Examples of the method offorming the coating film include a method in which varnish obtained bydissolving the photosensitive resin composition into a solvent isdirectly applied to a substrate in accordance with spin coating, barcoating or curtain coating and the formed layer is dried under a mildcondition or a method in which a varnish obtained by dissolving thephotosensitive resin composition into a solvent is applied to areleasing substrate made of a plastic sheet or a sheet of a metal suchas stainless steel and dried under a mild condition to prepare amaterial for coating and then the layer on the prepared material forcoating is transferred to a substrate by lamination with pressure.

The wave length of the radiation applied to the composition of thepresent invention can be suitably selected in accordance with the usedoxygen sensitizer. For example, when fullerene C60 is used as the oxygensensitizer, radiation having a wide range of wave length such as lightof ultraviolet region to visible region (250 to 780 nm), X-ray andelectron beams can be used. The exposure can be conducted by irradiatingthe light to the coating film through a mask which can shield area ofthe formed coating film where the resin composition will be removed.After the exposure, the development can be conducted by using an organicsolvent or an alkaline aqueous solution which can dissolve the resincomposition not exposed to the light. The resin composition in the areanot exposed to the light is dissolved while the resin composition in theexposed area has been made insoluble by the crosslinking bypolycondensation. As the result, the resin layer can be worked to formpatterns such as holes using the mask.

The cis-diene-substituted polyamic acids having the structural unitsrepresented by formulae [1] to [5] can be converted into polyimides bythe ring closure reaction with dehydration by heat curing the polyamicacids after the development. The condition of the heat curing reactionis not particularly limited. In general, it is preferable that thereaction is conducted by heating at 150 to 250° C. for 30 minutes ormore. The heating can be conducted by using heated air, irradiation ofinfrared light or heated plates. The heating can be ordinarily conductedin the atmosphere of the air. Where necessary, the heating may beconducted in the atmosphere of an inert gas such as nitrogen and carbondioxide or at a reduced pressure. It is not always necessary that thecis-diene-substituted polyimide is treated by the heat curing reaction.However, the heating at the above temperature condition gives the resinthe history at high temperature and heat resistance of the resin can beimproved. By using the resin composition of the present invention in theabove working steps, the patterned resin layer having excellent heatresistance can be formed by working at low temperatures and printedcircuit wiring boards, substrates for disposing semiconductor chips andsemiconductor devices having excellent properties can be produced.

To summarize the advantages of the invention, the photosensitive resincomposition of the present invention has excellent properties as a heatresistant photoresist of the negative type. The polyamic acid and thepolyimide used in the composition of the present invention are solublein solvents such as an alkaline aqueous solution in the original form.When the polyamic acid and the polyimide are crosslinked bypolycondensation with oxidation of the cis-diene group at the side chainwith the singlet oxygen generated by the effect of the oxygen sensitizersuch as fullerene C60, the polyamic acid and the polyimide becomeinsoluble in solvents. Therefore, practically useful patterns of thenegative type can be obtained with high sensitivity and high resolutionwhich cannot be achieved by conventional heat resist compositions. Inparticular, heat resistance of the resin film after formation of thepatterns can be remarkably improved by using a fullerene as the oxygensensitizer. The polyamic acid and the polyimide in which the main chainis bonded to the meta-positions of an aromatic ring substituted with amonovalent organic group having a cis-diene structure provides a resinhaving more excellent heat resistance than that provided by the polyamicacid and the polyimide in which the main chain is bonded to thepara-positions of an aromatic ring substituted with a monovalent organicgroup having a cis-diene structure. The printed wiring board, thesubstrate for disposing semiconductor chips and the semiconductor deviceof the present invention which are produced by using the composition ofthe present invention have excellent properties.

EXAMPLES

The present invention will be described more specifically with referenceto examples in the following. However, the present invention is notlimited to the examples.

Example 1

2-Hydroxy-3-methyl-1,4-phenylenediamine in an amount of 5.41 g (0.0392mol) and 8.55 g (0.0392 mol) of pyromellitic dianhydride were reacted in50 ml of N-methyl-2-pyrrolidone at the room temperature and a solutionof a polyamic acid having the structural unit expressed by formula [17]was obtained.

Separately, 5.00 g (0.0510 mol) of furfuryl alcohol was dissolved in 50ml of tetrahydrofuran and 4.90 g (0.0181 mol) of phosphorus tribromidewas added dropwise to the prepared solution. After the reaction mixturewas stirred for about 1.5 hours, water was added to the reaction mixtureand the organic component was extracted twice with 100 ml of ether. Theether layer was washed with sodium hydrogencarbonate and sodiumchloride, dried with 30 g of molecular sieves overnight and filtered toobtain an ether solution of furfuryl bromide. The product was confirmedto be furfuryl bromide by the analyses of the obtained solution inaccordance with ¹H-NMR and ¹³C-NMR.

Then, the solution of the polyamic acid prepared above was diluted byadding 150 ml of N-methyl-2-pyrrolidone so that the homogeneous reactioncan be conducted. To the diluted solution, the above ether solution inan amount such that 7.70 g (0.0510 mol) of furfuryl bromide wascontained and 6.50 g (0.0470 mol) of potassium carbonate were added andthe resultant mixture was stirred at 80° C. for about 2 hours. Thereaction solution was added to methanol to form reprecipitates and theobtained precipitates were dried in vacuo to obtain 16.3 g of a polyamicacid having the structural unit expressed by formula [18]. The result ofthe analysis of the product in accordance with ¹H-NMR showed thatfurfuryl group was introduced to 85% by mol of the hydroxyl groups ofthe diamine monomer units in the polyamic acid. The polyamic acid had amolecular weight of 80,000.

The obtained polyamic acid having the structural unit expressed byformula [18] in an amount of 15.0 g was dissolved into 100 ml ofN-methyl-2-pyrrolidone and 0.072 g (0.0001 mol) of fullerene C60 [99.98%by weight; manufactured by TERM Company] as the oxygen sensitizer wasadded to the obtained solution.

The prepared solution was applied to a silicon wafer by spin coater anddried by heating at 80° C. for 10 minutes to form a coating film havinga dried thickness of 1.5 μm. The film was placed at a position of 30 cmfrom a 250 W ultra-high pressure mercury lamp. The film was exposed tothe light for 3 minutes through the negative type quartz photomask [atest chart of TOPPAN PRINTING Co., Ltd.]. After the exposure to thelight, the film was developed with a 1.0% by weight aqueous solution oftetramethyl-ammonium hydroxide until the surface of the silicon waferappeared in the unexposed area. After rinsing with water, an excellentresin pattern of the negative type could be obtained.

A resin layer was formed by heating the obtained resin pattern at 200°C. for 1 hour. The decrease in the weight of the obtained resin layerafter heating from the room temperature to 300° C. was measured using aTG/DTA apparatus [manufactured by SEIKO DENSHI KOGYO Co., Ltd.; TG/DTA220 type; the rate of raising the temperature: 10° C./minute] and wasfound to be 0.5% by weight.

Example 2

2,2′-Dihydroxy-3,3′-dimethyl-4,4′-diaminobiphenyl in an amount of 9.56 g(0.0392 mol) and 8.55 g (0.0392 mol) of pyromellitic dianhydride werereacted in 50 ml of N-methyl-2-pyrrolidone at the room temperature and asolution of a polyamic acid having the structural unit expressed byformula [19] was obtained.

The above solution of the polyamic acid was diluted by addition of 150ml of N-methyl-2-pyrrolidone so that the uniform reaction can beconducted. To the diluted solution, an ether solution of furfurylbromide which was prepared in accordance with the same procedures asthose conducted in Example 1 in an amount such that 7.70 g (0.0510 mol)of furfuryl bromide was contained and 6.50 g (0.0470 mol) of potassiumcarbonate were added and the resultant mixture was stirred at 80° C. forabout 2 hours. The reaction solution was added to methanol to formreprecipitates and the obtained precipitates were dried in vacuo toobtain 19.5 g of a polyamic acid having the structural unit expressed byformula [20]. The result of the analysis of the product in accordancewith ¹H-NMR showed that furfuryl group was introduced to 86% by mol ofthe hydroxyl groups of the diamine monomer units in the polyamic acid.

The obtained polyamic acid having the structural unit expressed byformula [20] in an amount of 15.0 g was dissolved into 100 ml ofN-methyl-2-pyrrolidone and 0.072 g (0.0001 mol) of fullerene C60 [99.98%by weight; manufactured by TERM Company] as the oxygen sensitizer wasadded to the obtained solution.

The prepared solution was applied to a silicon wafer by spin coater anddried by heating at 80° C. for 10 minutes to form a coating film havinga dried thickness of 1.5 μm. The film was placed at a position of 30 cmfrom a 250 W ultra-high pressure mercury lamp. The film was exposed tothe light for 3 minutes through the negative type quartz photomask [atest chart of TOPPAN PRINTING Co., Ltd.]. After the exposure to thelight, the film was developed with a 1.0% by weight aqueous solution oftetramethyl-ammonium hydroxide until the surface of the silicon waferappeared in the unexposed area. After rinsing with water, an excellentresin pattern of the negative type could be obtained.

A resin layer was formed by heating the obtained resin pattern at 200°C. for 1 hour. The decrease in the weight of the obtained resin layerafter heating from the room temperature to 300° C. was measured inaccordance with the same method as that used in Example 1 and was foundto be 0.8% by weight.

Example 3

In accordance with the same procedures as those conducted in Examples 1except that an ether solution containing 8.52 g (0.0510 mol) of2-thienylmethyl bromide was used in place of the ether solution offurfuryl bromide, 20.1 g of a polyamic acid having the structural unitexpressed by formula [21] was obtained. The result of the analysis ofthe product in accordance with ¹H-NMR showed that 2-thienylmethyl groupwas introduced to 88% by mol of the hydroxyl groups of the diaminemonomer units in the polyamic acid.

The obtained polyamic acid having the structural unit expressed byformula [21] in an amount of 15.0 g was dissolved into 100 ml ofN-methyl-2-pyrrolidone and 0.072 g (0.0001 mol) of fullerene C60 [99.98%by weight; manufactured by TERM Company] as the oxygen sensitizer wasadded to the obtained solution.

The prepared solution was applied to a silicon wafer by spin coater anddried by heating at 80° C. for 10 minutes to form a coating film havinga dried thickness of 1.5 μm. The film was placed at a position of 30 cmfrom a 250 W ultra-high pressure mercury lamp. The film was exposed tothe light for 3 minutes through the negative type quartz photomask [atest chart of TOPPAN PRINTING Co., Ltd.]. After the exposure to thelight, the film was developed with a 1.0% by weight aqueous solution oftetramethyl-ammonium hydroxide until the surface of the silicon waferappeared in the unexposed area. After rinsing with water, an excellentresin pattern of the negative type could be obtained.

A resin layer was formed by heating the obtained resin pattern at 200°C. for 1 hour. The decrease in the weight of the obtained resin layerafter heating from the room temperature to 300° C. was measured inaccordance with the same method as that used in Example 1 and was foundto be 0.7% by weight.

Example 4

A solution was prepared and applied to a silicon wafer by spin coaterand dried by heating to form a coating film and the formed coating filmwas tightly attached with a mask and exposed to light using anultra-high pressure mercury lamp in accordance with the same proceduresas those conducted in Example 1 except that 0.102 g (0.0001 mol) of rosebengal was added as the oxygen sensitizer in place of 0.072 g (0.0001mol) of fullerene C60 [99.98% by weight; manufactured by TERM Company].

After the exposure to the light, the film was developed with a 1.0% byweight aqueous solution of tetramethylammonium hydroxide until thesurface of the silicon wafer appeared in the unexposed area. Afterrinsing with water, a resin pattern of the negative type could beobtained.

A resin layer was formed by heating the obtained resin pattern at 200°C. for 1 hour. The decrease in the weight of the obtained resin layerafter heating from the room temperature to 300° C. was measured inaccordance with the same method as that used in Example 1 and was foundto be 3.6% by weight.

Example 5

2,2-bis(3-Furfuryloxy-4-aminophenyl)propane in an amount of 16.39 g(0.0392 mol) and 8.55 g (0.0392 mol) of pyromellitic dianhydride werereacted in 200 ml of N-methyl-2-pyrrolidone at the room temperature anda solution of a polyamic acid was obtained. The obtained solution wastreated by reprecipitation with methanol and the obtained precipitateswere dried in vacuo to obtain 24.5 g of a polyamic acid having thestructural unit expressed by formula [22].

The obtained polyamic acid having the structural unit expressed byformula [22] in an amount of 15.0 g was dissolved into 100 ml ofN-methyl-2-pyrrolidone and 0.072 g (0.0001 mol) of fullerene C60 [99.98%by weight; manufactured by TERM Company] as the oxygen sensitizer wasadded to the obtained solution.

The prepared solution was applied to a silicon wafer by spin coater anddried by heating at 80° C. for 10 minutes to form a coating film havinga dried thickness of 1.5 μm. The film was placed at a position of 30 cmfrom a 250 W ultra-high pressure mercury lamp. The film was exposed tothe light for 3 minutes through the negative type quartz photomask [atest chart of TOPPAN PRINTING Co., Ltd.]. After the exposure to thelight, the film was developed with a 1.0% by weight aqueous solution oftetramethyl-ammonium hydroxide until the surface of the silicon waferappeared in the unexposed area. After rinsing with water, an excellentresin pattern of the negative type could be obtained.

A resin layer was formed by heating the obtained resin pattern at 200°C. for 1 hour. The decrease in the weight of the obtained resin layerafter heating from the room temperature to 300° C. was measured inaccordance with the same method as that used in Example 1 and was foundto be 1.2% by weight.

Example 6

3,3′-Difurfuryloxy-4,4′-diaminobiphenyl in an amount of 14.74 g (0.0392mol) and 17.41 g (0.0392 mol) of 4,4′-hexafluoroisopropylidenediphthalicanhydride were reacted in 200 ml of N-methyl-2-pyrrolidone at the roomtemperature and a solution of a polyamic acid was obtained. The obtainedsolution was treated by reprecipitation with methanol and the obtainedprecipitates were dried in vacuo to obtain 31.6 g of a polyamic acidhaving the structural unit expressed by formula [23].

The obtained polyamic acid having the structural unit expressed byformula [23] in an amount of 15.0 g was dissolved into 100 ml ofN-methyl-2-pyrrolidone and 0.072 g (0.0001 mol) of fullerene C60 [99.98%by weight; manufactured by TERM Company] as the oxygen sensitizer wasadded to the obtained solution.

The prepared solution was applied to a silicon wafer by spin coater anddried by heating at 80° C. for 10 minutes to form a coating film havinga dried thickness of 1.5 μm. The film was placed at a position of 30 cmfrom a 250 W ultra-high pressure mercury lamp. The film was exposed tothe light for 3 minutes through the negative type quartz photomask [atest chart of TOPPAN PRINTING Co., Ltd.]. After the exposure to thelight, the film was developed with a 1.0% by weight aqueous solution oftetramethyl-ammonium hydroxide until the surface of the silicon waferappeared in the unexposed area. After rinsing with water, a remarkablyexcellent resin pattern of the negative type could be obtained.

A resin layer was formed by heating the obtained resin pattern at 200°C. for 1 hour. The decrease in the weight of the obtained resin layerafter heating from the room temperature to 300° C. was measured inaccordance with the same method as that used in Example 1 and was foundto be 0.8% by weight.

Using the solution obtained above, a coating film was formed,preliminarily heated and exposed to a prescribed amount of light. Then,the coating film was developed for 2 minutes with a 1.0% by weightaqueous solution of tetramethylammonium hydroxide. By repeating thisprocedure using different amounts of the light, a characteristic curveshowing the sensitivity was prepared and the minimum amount of light tomake the film insoluble was obtained. The minimum amount of light was2×10 mJ·cm⁻².

Example 7

A solution was prepared and applied to a silicon wafer by spin coaterand dried by heating to form a coating film and the formed coating filmwas tightly attached with a mask and exposed to light using anultra-high pressure mercury lamp in accordance with the same proceduresas those conducted in Examples 6 except that 0.053 g (0.0001 mol) ofrubrene was added as the oxygen sensitizer in place of 0.072 g (0.0001mol) of fullerene C60 [99.98% by weight; manufactured by TERM Company].

After the exposure to the light, the film was developed with a 1.0% byweight aqueous solution of tetramethylammonium hydroxide until thesurface of the silicon wafer appeared in the unexposed area. Afterrinsing with water, a resin pattern of the negative type could beobtained.

A resin layer was formed by heating the obtained resin pattern at 200°C. for 1 hour. The decrease in the weight of the obtained resin layerafter heating from the room temperature to 300° C. was measured inaccordance with the same method as that used in Example 1 and was foundto be 1.8% by weight.

In accordance with the same procedure as that conducted in Example 6, acharacteristic curve showing the sensitivity was prepared and theminimum amount of light to make the film insoluble was obtained. Theminimum amount of light was 8×10 mJ·cm⁻².

Example 8

3,3-Diamino-4,4′-dihydroxybiphenyl in an amount of 8.47 g (0.0392 mol)and 8.55 g (0.0392 mol) of pyromellitic dianhydride were stirred in 50ml of N-methyl-2-pyrrolidone at 60° C. and a solution of a polyamic acidwas obtained.

Separately, 5.00 g (0.0510 mol) of furfuryl alcohol was dissolved in 50ml of tetrahydrofuran and 4.90 g (0.0181 mol) of phosphorus tribromidewas added dropwise to the prepared solution while the solution was keptat 0° C. After the solution was stirred for about 2 hours, water wasadded to the solution and the organic component was extracted twice with100 ml of ether. The ether layer was washed with sodiumhydrogencarbonate, dried with 30 g of molecular sieves overnight andfiltered to obtain an ether solution of furfuryl bromide. The productwas confirmed to be furfuryl bromide by the analyses of the obtainedsolution in accordance with FT-IR, ¹H-NMR and ¹³C-NMR.

Then, the above solution of the polyamic acid was diluted by adding 150ml of N-methyl-2-pyrrolidone. To the diluted solution, the above ethersolution in an amount such that 7.70 g (0.0510 mol) of furfuryl bromidewas contained and 6.50 g of potassium carbonate were added and theresultant solution was stirred at 80° C. for about 2 hours. The reactionsolution was added to methanol to coagulate reprecipitates and theobtained precipitates were dried in vacuo to obtain 16.3 g of a polyamicacid having the structural unit represented by formula [24]. In formula[24], Z represents hydrogen or furfuryl group. The result of theanalysis of the product in accordance with ¹H-NMR showed that furfurylgroup was introduced to 80% by mol of the hydroxyl groups of the diaminemonomer units in the polyamic acid. The polyamic acid had a molecularweight of 70,000.

High purity fullerene C60 [99.98% by weight; manufactured by TERMCompany] in an amount of 0.75 g and 10.0 g of the above polyamic acidpartially substituted with furfuryl group were dissolved in 50 ml ofγ-butyrolactone/1,1,2,2-tetrachloroethylene (the ratio by volume: 70/30)to prepare a homogeneous solution. After the prepared solution wasfiltered through a filter having a pore size of 0.1 μm, the solution wasapplied to a silicon wafer by spin coater and dried by heating at 80° C.for 10 minutes to form a coating film having a thickness of 2 μm. Thecoating film was exposed by a 500 W ultra-high pressure mercury lampthrough a photomask [a test chart of TOPPAN PRINTING Co., Ltd.] and,immediately thereafter, dipped into a 10% by weight aqueous solution oftetramethylammonium hydroxide for 30 seconds for the development. Theunexposed area was dissolved and completely removed and a resin patternhaving a line width of 5 μm or less was formed.

The obtained resin pattern was heated at 200° C. for 1 hour to form aresin layer. The decrease in the weight of this resin layer afterheating from the room temperature to 300° C. was measured in accordancewith the same procedure as that conducted in Example 1 and was found tobe 0.3% by weight.

Example 9

2,2-bis(3-Amino-4-hydroxyphenyl)hexafluoropropane in an amount of 14.36g (0.0392 mol) and 8.55 g (0.0392 mol) of pyromellitic dianhydride werestirred in 50 ml of N-methyl-2-pyrrolidone at 60° C. and a solution of apolyamic acid was obtained.

Then, the above solution of the polyamic acid was diluted by adding 150ml of N-methyl-2-pyrrolidone. To the diluted solution, an ether solutioncontaining 7.70 g of furfuryl bromide and 6.50 g of potassium carbonatewere added and the resultant solution was stirred at 80° C. for about 2hours. The reaction solution was added to methanol to coagulatereprecipitates and the obtained precipitates were dried in vacuo toobtain 20.3 g of a polyamic acid having the structural unit representedby formula [25]. In formula [25], Z represents hydrogen or furfurylgroup. The result of the analysis of the product in accordance with¹H-NMR showed that furfuryl group was introduced to 80% by mol of thehydroxyl groups of the diamine monomer units in the polyamic acid. Thepolyamic acid had a molecular weight of about 50,000.

High purity fullerene C60 [99.98% by weight; manufactured by TERMCompany] in an amount of 0.75 g and 10.0 g of the above polyamic acidpartially substituted with furfuryl group were dissolved in 50 ml ofg-butyrolactone/1,1,2,2-tetrachloroethylene (the ratio by volume: 70/30)to prepare a homogeneous solution. After the prepared solution wasfiltered through a filter having a pore size of 0.1 μm, the solution wasapplied to a silicon wafer by spin coater and dried by heating at 80° C.for 10 minutes to form a coating film having a thickness of 2 μm. Thecoating film was exposed to the light of a 500 W ultra-high pressuremercury lamp through a photomask [a test chart of TOPPAN PRINTING Co.,Ltd.] and, immediately thereafter, dipped into a 10% by weight aqueoussolution of tetramethylammonium hydroxide for 30 seconds for thedevelopment. The unexposed area was dissolved and completely removed anda resin pattern having a line width of 5 μm or less was formed.

The obtained resin pattern was heated at 200° C. for 1 hour to form aresin layer. The decrease in the weight of this resin layer afterheating from the room temperature to 300° C. was measured using theTG/DTA apparatus in accordance with the same procedure as that conductedin Example 1 and was found to be 0.5% by weight.

Reference Example 1 Preparation of 3,5-diaminobenzyl-2-furoate

Preparation of 3,5-dinitrobenzyl-2-furoate: In a 500 ml separable flaskequipped with a stirrer, a reflux condenser cooled with water, athermometer and a dropping funnel, 37.0 g of 3,5-dinitrobenzyl alcoholwas dissolved into 100 ml of pyridine. While the prepared solution wascooled at 0 to 5° C., 53.1 g of 2-furoyl chloride was added dropwise tothe solution. After the addition was completed, the reaction solutionwas warmed to the room temperature and stirred for 2 hours. Then, 400 mlof water was added to the solution and the solid substance was separatedby filtration. The obtained solid substance was recrystallized fromethyl alcohol/water (the volume ratio: 80/20) to obtain 47 g of3,5-dinitrobenzyl-2-furoate. The yield was 86% and the melting point was116 to 117° C.

Preparation of 3,5-diaminobenzyl-2-furoate: In a 1 liter separable flaskequipped with a stirrer and a reflux condenser cooled with water, 14.6 gof 3,5-dinitrobenzyl-2-furoate was dissolved into 120 ml of ethylacetate and 80 ml of ethyl alcohol. To the prepared solution, 120 ml ofa saturated aqueous solution of ammonium chloride was added and then 100g of powder of indium metal was added. The obtained mixture was stirredunder the refluxing condition for 17 hours to allow the reduction toproceed. After the reaction was completed, the reaction solution wastransferred to a 2 liter beaker. One liter of water was added to thereaction solution and the solid substance was removed by filtration.After pH of the filtrate was adjusted to 9 by adding a 2N aqueoussolution of sodium hydroxide, the filtrate was extracted with ethylacetate and the ethyl acetate layer was dried with magnesium sulfate.Then, ethyl acetate was removed by distillation at a reduced pressureand 10 g of a crude product was obtained. The crude product was purifiedin accordance with the silica gel column chromatography to obtain 4.6 gof 3,5-diaminobenzyl-2-furoate. The yield was 40%. This product wasrecrystallized from ethyl alcohol and needle crystals having a meltingpoint of 119 to 121.1° C. were obtained.

The synthesis and the purification were conducted twice more inaccordance with the same procedures.

Example 10

3,5-Diaminobenzyl-2-furoate synthesized in Reference Example 1 in anamount of 9.09 g (0.0392 mol) and 17.41 g (0.0392 mol) of4,4′-hexafluoroisopropylidenediphthalic anhydride were stirred in 50 mlof γ-butyrolactone at the room temperature and a solution of a polyamicacid having the structural unit expressed by formula [26] was obtained.The obtained solution was diluted by adding 50 ml ofN-methyl-2-pyrrolidone. The diluted solution was poured intowater/methanol (the volume ratio: 75/25) to coagulate and precipitatepolyamic acid. After filtration and drying in vacuo, 25.9 g of apolyamic acid having the structural unit expressed by formula [26] wasobtained as light yellow powder.

High purity fullerene C60 [99.98% by weight; manufactured by TERMCompany] in an amount of 0.75 g and 10.0 g of the above polyamic acidsubstituted with furoyl group were dissolved in 50 ml ofγ-butyrolactone/1,1,2,2-tetrachloroethylene (the ratio by volume: 70/30)to prepare a homogeneous solution. After the prepared solution wasfiltered through a filter having a pore size of 0.1 μm, the solution wasapplied to a silicon wafer by spin coater and dried by heating at 80° C.for 10 minutes to form a coating film having a thickness of 2 μm. Thecoating film was exposed to the light of a 500 W ultra-high pressuremercury lamp through a photomask [a test chart of TOPPAN PRINTING Co.,Ltd.] and, immediately thereafter, dipped into a 10% by weight aqueoussolution of tetramethylammonium hydroxide for 30 seconds for thedevelopment. The unexposed area was dissolved and completely removed anda resin pattern having a line width of 5 μm or less was formed.

The obtained resin pattern was heated at 200° C. for 1 hour to form aresin layer. The decrease in the weight of this resin layer afterheating from the room temperature to 300° C. was measured in accordancewith the same procedure as that conducted in Example 1 and was found tobe 0.3% by weight.

Reference Example 2 Synthesis of3,3′-diamino-4,4′-di-2-furoylaminobiphenyl

Preparation of 3,3′-dinitro-4,4′-di-2-furoylaminobiphenyl: In a 500 mlseparable flask equipped with a stirrer, a reflux condenser cooled withwater, a thermometer and a dropping funnel, 10.96 g of3,3′-dinitro-4,4′-diaminobiphenyl was dissolved into 200 ml ofN,N-dimethylformamide and then 20 ml of pyridine was added to thesolution. While the prepared solution was cooled at 3 to 14° C., 12.53 gof 2-furoyl chloride was added dropwise to the solution. After theaddition was completed, the reaction solution was warmed to the roomtemperature and stirred for further 5 hours. Then, 80 ml of 2Nhydrochloric acid and 100 ml of water were added to the solution and thesolid substance was separated by filtration. The obtained solidsubstance was washed well with water and dried in a reduced pressure toobtain 15.0 g of 3,3′-dinitro-4,4′-di-2-furoylaminobiphenyl. The yieldwas 81%.

Preparation of 3,3′-diamino-4,4′-di-2-furoylaminobiphenyl: Into aseparable flask equipped with a stirrer and a reflux condenser cooledwith water, 7.4 g of 3,3′-dinitro-4,4′-di-2-furoylaminobiphenyl, 100 mlof N-methyl-2-pyrrolidone and 75 ml of ethyl alcohol were placed. Afteradding 40 ml of a saturated aqueous solution of ammonium chloride, 25.6g of powder of indium metal was added to the prepared solution. Theobtained mixture was stirred at 80° C. for 1 hour. After the reactionsolution was cooled to the room temperature, the solid substance wasremoved by filtration. The filtrate was concentrated to about one halfat a reduced pressure. To the concentrated filtrate, 300 ml of water wasadded and the formed solid substance was separated by filtration toobtain 2.9 g of a crude product. The crude product was purified inaccordance with the silica gel column chromatography to obtain 1.5 g of3,3′-diamino-4,4′-di-2-furoylaminobiphenyl. The yield of the isolatedproduct was 23%. This product was recrystallized fromN-methyl-2-pyrrolidone/ethyl acetate (the volume ratio: 25/75) andneedle crystals having a decomposition temperature of 256 to 259° C.were obtained.

The synthesis and the purification were conducted 12 times more inaccordance with the same procedures.

Example 11

3,3′-Diamino-4,4′-di-2-furoylaminobiphenyl synthesized in ReferenceExample 2 in an amount of 15.76 g (0.0392 mol) and 17.41 g (0.0392 mol)of 4,4′-hexafluoroisopropylidenediphthalic anhydride were stirred in 50ml of γ-butyrolactone at the room temperature and a solution of apolyamic acid having the structural unit expressed by formula [27] wasobtained. The obtained solution was diluted by adding 50 ml ofN-methyl-2-pyrrolidone. The diluted solution was poured intowater/methanol (the volume ratio: 75/25) to coagulate and precipitatethe polyamic acid. After filtration and drying in vacuo, 31.5 g of apolyamic acid having the structural unit expressed by formula [27] wasobtained as light yellow powder.

High purity fullerene C60 [99.98% by weight; manufactured by TERMCompany] in an amount of 0.75 g and 10.0 g of the above polyamic acidsubstituted with furoyl group were dissolved in 50 ml ofγ-butyrolactone/toluene (the ratio by volume: 60/40) to prepare ahomogeneous solution.

After the prepared solution was filtered through a filter having a poresize of 0.1 μm, the solution was applied to a silicon wafer by spincoater and dried by heating at 80° C. for 10 minutes to form a coatingfilm having a thickness of 2 μm. The coating film was exposed to thelight of a 500 W ultra-high pressure mercury lamp through a photomask [atest chart of TOPPAN PRINTING Co., Ltd.] and, immediately thereafter,dipped into a 10% by weight aqueous solution of tetramethylammoniumhydroxide for 30 seconds for the development. The unexposed area wasdissolved and completely removed and a resin pattern having a line widthof 5 μm or less was formed.

The obtained resin pattern was heated at 200° C. for 1 hour to form aresin layer. The decrease in the weight of this resin layer afterheating from the room temperature to 300° C. was measured in accordancewith the same procedure as that conducted in Example 1 and was found tobe 0.2% by weight.

Comparative Example 1

A polyamic acid partially having furfuryl group was synthesized inaccordance with the same procedures as those conducted in Example 1except that furfuryl bromide which was reacted with the polyamic acidhaving the structural unit expressed by formula [17] was used in anamount of 1.78 g (0.0118 mol). The results of the ¹H-NMR analysis showedthat furfuryl group was introduced to 8% by mol of the hydroxyl groupsof the diamine monomer units in the polyamic acid.

The obtained polyamic acid partially substituted with furfuryl group inan amount of 12.0 g was dissolved into 80 ml of N-methyl-2-pyrrolidone.To this solution, 0.0576 g (0.00008 mol) of fullerene C60 [99.98% byweight; manufactured by TERM Company] as the oxygen sensitizer wasadded.

The prepared solution was applied to a silicon wafer by spin coater anddried by heating to form a coating film and the formed coating film wastightly attached with a mask and exposed to light using an ultra-highpressure mercury lamp in accordance with the same procedures as thoseconducted in Example 1. After the exposure to the light, the film wasdeveloped with a 1.0% by weight aqueous solution of tetramethylammoniumhydroxide. All portions of the coating film including the exposedportions were dissolved into the developer and no resin pattern could beobtained.

The results of Examples 1 to 11 and Comparative Example 1 are shown inTable 1.

TABLE 1 Fraction Decrease Minimum Structure substituted in weight amountof of with Oxygen after light to make polyamic cis-Diene cis-dienesensit- heating insoluble acid structure (% by mol) izer (% by wt.) (mJ· cm⁻²) Example 1 Formula [18] furan 85 fullerene 0.5 — Example 2Formula [20] furan 86 fullerene 0.8 — Example 3 Formula [21] thiophene88 fullerene 0.7 — Example 4 Formula [18] furan 85 rose bengal 3.6 —Example 5 Formula [22] furan 100 fullerene 1.2 — Example 6 Formula [23]furan 100 fullerene 0.8 2 × 10 Example 7 Formula [23] furan 100 rubrene1.8 8 × 10 Example 8 Formula [24] furan 80 fullerene 0.3 — Example 9Formula [25] furan 80 fullerene 0.5 — Example 10 Formula [26] furan 100fullerene 0.3 — Example 11 Formula [27] furan 100 fullerene 0.2 —Comparative Formula [11] furan 8 fullerene —¹⁾ — Example 1 ¹⁾Dissolvedinto the developing solution even after exposure to the light

As shown in Table 1, the resin layers showing small decreases in theweight after heating and exhibiting excellent heat resistance could beobtained from the photosensitive resin compositions of Examples 1 to 11which contained cis-diene-substituted polyamic acids having thestructural units represented by general formulae [1] to [5] and theoxygen sensitizer. In particular, the resin layers obtained from theresin compositions of Examples 1 to 3, 5 to 6 and 9 to 11 in which afullerene was used as the oxygen sensitizer showed smaller decreases inthe weight after heating and exhibited more excellent heat resistancethan those of the resin layers of Example 4 in which rose bengal wasused as the oxygen sensitizer and the resin layers of Example 7 in whichrubrene was used as the oxygen sensitizer. Among the resin layersobtained from the photosensitive resin compositions using a fullerene asthe oxygen sensitizer, the resin layers obtained from the photosensitiveresin compositions of Examples 8 to 11 in which the main chain is bondedto the meta-positions of the aromatic ring showed smaller decreases inthe weight after heating and exhibited more excellent heat resistancethan those of the resin layers obtained from the photosensitive resincompositions of Examples 1 to 3 and 5 to 6 in which the main chain isbonded to the para-positions of the aromatic ring Regarding to thephotosensitive resin compositions containing the cis-diene-substitutedpolyamic acid having structural unit represented by formula 23, thephotosensitive resin composition of Example 6 in which a fullerene wasused as the oxygen sensitizer showed better sensitivity than that of thephotosensitive resin composition of Example 7 in which rubrene was usedas the oxygen sensitizer.

On the other hand, the photosensitive resin composition of ComparativeExample 1 containing the structural unit substituted with a cis-dienewhich is represented by general formula [1] in an amount of 8% of thetotal diamine structural units was dissolved into the developer evenafter the exposure to the light and resin patterns could not be formed.

What is claimed is:
 1. A photosensitive resin composition whichcomprises (a) an oxygen sensitizer and (b) a cis-diene-substitutedpolyamic acid or a polyimide having a structural unit represented byformula (4):

wherein at least one of R²², R²³, R²⁴ and R²⁵ represents a monovalentorganic group having a cis-diene structure; the rest of R²², R²³, R²⁴and R²⁵ each independently represents hydrogen, a hydroxyl group, acarboxyl group, an alkyl group having 1 to 20 carbon atoms or an alkoxygroup having 1 to 20 carbon atoms; X¹ and X² each independentlyrepresents oxygen, sulfur, an alkylene group having 1 to 4 carbon atoms,an alkylidene group having 1 to 4 carbon atoms or an alkyleneoxy grouphaving 1 to 4 carbon atoms; Ar¹ and Ar² each independently represents adivalent aromatic group; and l₁, l₂, m₁ and m₂ each independentlyrepresents 0 or 1, except that m₁ represents 1 when l₁ represents 1, andm₂ represents 1 when l₂ represents
 1. 2. A photosensitive resincomposition according to claim 1, wherein the oxygen sensitizer has anexcited triplet energy of 22.5 kcal/mol or more.
 3. A photosensitiveresin composition according to claim 2, wherein the oxygen sensitizer isin an amount of 0.01 to 20 parts by weight or more per 100 parts byweight of the cis-diene-substituted polyamic acid or polyamide.
 4. Aphotosensitive resin composition according to claim 3, wherein thecis-diene-substituted polyamic acid or polyamide has a structural unitselected from the group consisting of


5. A photosensitive resin composition which comprises (a) an oxygensensitizer and (b) a cis-diene-substituted polyamic acid or a polyimidehaving a structural unit represented by formula (5):

wherein at least one of R²⁶, R²⁷, R²⁸, R²⁹, R³⁰, R³¹, R³² and R³³represents a monovalent organic group having a cis-diene structure; therest of R²⁶, R²⁷, R²⁸, R²⁹, R³⁰, R³¹, R³² and R³³ each independentlyrepresents a hydrogen atom, a hydroxyl group, a carboxyl group, an alkylgroup having 1 to 20 carbon atoms or an alkoxy group having 1 to 20carbon atoms; Y¹ represents oxygen, sulfur, an optionally substitutedalkylene group having 1 to 4 carbon atoms, an optionally substitutedalkylidene group having 1 to 4 carbon atoms or an optionally substitutedalkyleneoxy group having 1 to 4 carbon atoms; and n₁ represents 0 or 1.6. A photosensitive resin composition according to claim 5, wherein Y¹is


7. A photosensitive resin composition according to claim 5, wherein theoxygen sensitizer has an excited triplet energy of 22.5 kcal/mol ormore.
 8. A photosensitive resin composition according to claim 7,wherein the oxygen sensitizer is in an amount of 0.01 to 20 parts byweight or more per 100 parts by weight of the cis-diene-substitutedpolyamic acid or polyamide.
 9. A photosensitive resin compositionaccording to claim 8, wherein the cis-diene-substituted polyamic acid orpolyimide has a structural unit selected from the group consisting of


10. A photosensitive resin composition according to any of claims 1, 5,6 and 2, wherein the cis-diene structure is a cyclopentadiene, furan,thiophene or pyrrole structure.
 11. A photosensitive resin compositionaccording to claim 10, wherein the oxygen sensitizer is fullerene.
 12. Aphotosensitive resin composition according to any of claims 1, 5, 6 and2, wherein the oxygen sensitizer is a fullerene.